In related art, in one example, Patent Literatures 1 to 3 below disclose techniques of estimating an amount of lens shading using an image acquired by photographing a plurality of times while changing photographing conditions. Specifically, Patent Literature 1 discloses estimation of an amount of lens shading performed using an image having a difference in f-number, focal length, and presence or absence of flash light. In addition, Patent Literature 2 discloses estimation of an amount of lens shading performed using an image having a difference in F-number. In addition, Patent Literature 3 discloses estimation of an amount of lens shading performed using an image having a difference in exposure conditions.